Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| cloning of the reca gene from a free-living leptospire and distribution of reca-like protein among spirochetes. | a recombinant plasmid carrying the reca gene of leptospira biflexa serovar patoc was isolated from a cosmid library of genomic dna by complementation of an escherichia coli reca mutation. the cloned serovar patoc reca gene efficiently restored resistance to uv radiation and methyl methanesulfonate. recombination proficiency was also restored, as measured by the formation of lac+ recombinants from duplicated mutant lacz genes. additionally, the cloned reca gene increased the spontaneous and mitom ... | 1991 | 2036006 |
| molecular cloning and sequence analysis of antigen gene tdpa of treponema denticola. | we isolated and characterized an immunogenic protein of an oral spirochete, treponema denticola johnson. a genomic dna library constructed with bacteriophage lambda embl3 as a vector was immunologically screened with a rabbit antiserum against the whole cells. using western immunoblot analysis, we found a particular clone encoding an antigen with a molecular weight of 53,000; we designated the antigen as t. denticola protein a (tdpa). complete sequence determination revealed an open reading fram ... | 1991 | 2037356 |
| compilation of dna sequences of escherichia coli (update 1991). | we have compiled the dna sequence data for e. coli available from the genbank and embl data libraries and over a period of several years independently from the literature. this is the third listing replacing and increasing the former listing roughly by one fifth. however, in order to save space this printed version contains dna sequence information only. the complete compilation is now available in machine readable form from the embl data library (ecd release 6). after deletion of all detected o ... | 1991 | 2041799 |
| an assay for proteinases and their inhibitors based on dna/ethidium bromide fluorescence. | proteinases and their inhibitors have become the subject of intense research interest recently, since they control a multitude of very important biological processes, from the development of lambda phage to hypertension in humans. we have developed a simple and sensitive assay for detecting the activity of proteinases and of their proteinase inhibitors. the assay is based on ethidium bromide fluorescence, according to the following principles: (i) ethidium bromide increases its fluorescence by 2 ... | 1991 | 2042745 |
| involvement of fixlj in the regulation of nitrogen fixation in azorhizobium caulinodans. | a gene bank of azorhizobium caulinodans dna constructed in the bacteriophage lambda gem11 was screened with rhizobium meliloti fixl and fixj genes as probes. one positive recombinant phage, ors lambda l, was isolated. the nucleotide sequence of a 3.7 kb fragment was established. two open reading frames of 1512bp and 613bp were identified as fixl and fixj. kanamycin cartridges were inserted into the cloned fixl and fixj genes and recombined into the host genome. the resulting mutants were nif- fi ... | 1991 | 2046550 |
| preproabrin: genomic cloning, characterisation and the expression of the a-chain in escherichia coli. | synthetic oligonucleotides representing all possible sequences of an n-terminal and an internal region of the a-chain of abrin c were used to generate a probe specific for abrin-related sequences using the polymerase chain reaction on abrus precatorius genomic dna. a lambda phage library constructed from genomic dna isolated from leaf tissue of a. precatorius was screened and positive hybridising clones were characterised by restriction enzyme analysis. the coding regions of unique clones were c ... | 1991 | 2050149 |
| purification and characterization of a novel 5' exodeoxyribonuclease from the yeast saccharomyces cerevisiae. | we have isolated from yeast cells an exonuclease which preferentially attacks double-stranded dna from the 5' ends producing 5'-mononucleotides as reaction products. a second typical product is a full-length single-stranded dna complement, suggesting that the enzyme hydrolyzes one dna strand in a processive manner before it associates with another dna substrate to initiate a new reaction cycle. its biochemical properties suggest that the enzyme is unlike the yeast exonucleases which have been re ... | 1991 | 2050153 |
| molecular cloning of cdna for the b beta subunit of xenopus fibrinogen, the product of a coordinately-regulated gene family. | fibrinogen, the principal blood-clotting protein, is made up of three different subunits synthesized in the liver. in vitro administration of glucocorticoids to liver cells from the frog xenopus laevis causes a dramatic increase in fibrinogen synthesis. investigations of molecular mechanisms underlying this hormonal stimulation at the mrna level require cdna clones complementary to the mrnas coding for the three fibrinogen subunits, called a alpha, b beta, and gamma. we describe here the isolati ... | 1991 | 2050271 |
| dna bending induced by cro protein binding as demonstrated by gel electrophoresis. | we report an approach for studying protein-induced dna bends in solution that is based on measuring the sizes of circular dna molecules by using two-dimensional gel electrophoresis. these circular fragments are obtained by ligating short synthetic oligonucleotides containing a protein-recognition region in the presence of protein. oligonucleotides 21-base-pairs-long containing the or3 recognition site were synthesized and ligated in both the presence and the absence of the cro repressor from lam ... | 1991 | 2052610 |
| the murine gene encoding secreted phosphoprotein 1 (osteopontin): promoter structure, activity, and induction in vivo by estrogen and progesterone. | secreted phosphoprotein 1 (spp-1) is a 41.5-kda bone sialoprotein presumed to be important in the development and functioning of a number of mammalian organs and possibly also in the progression of malignancies. we report here the isolation of a phage lambda genomic clone of the murine spp-1 gene containing the promoter and first six exons (4.6 kb of the 5.7-kb gene). we have found another exon located 5' to the 'exon 1' reported by miyazaki et al. [j. biol. chem. 265 (1990) 14432-14438]. the dn ... | 1991 | 2055467 |
| cloning of the structural gene for clostridium botulinum type c1 toxin and whole nucleotide sequence of its light chain component. | the toxigenicity of clostridium botulinum type c1 is mediated by specific bacteriophages. dna was extracted from one of these phages. two dna fragments, 3 and 7.8 kb, which produced the protein reacting with antitoxin serum were cloned by using bacteriophage lambda gt11 and escherichia coli. both dna fragments were then subcloned into puc118 plasmids and transferred into e. coli cells. the nucleotide sequences of the cloned dna fragments were analyzed by the dideoxy chain termination method, and ... | 1991 | 2059039 |
| molecular cloning of a glutathione s-transferase overproduced in an insecticide-resistant strain of the housefly (musca domestica). | we report the cloning and sequencing of a glutathione s-transferase (gst) gene from the housefly musca domestica. a cdna lambda gt11 library was prepared from the organophosphate insecticide-resistant housefly strain cornell-r--a variant that has elevated gst activity. the lambda phage gst clone was identified on the basis of its ability to cross-hybridize to a gst dna probe from drosophila melanogaster. based on amino acid homology to other gsts and expression of gst activity in escherichia col ... | 1991 | 2062307 |
| analysis of a marine picoplankton community by 16s rrna gene cloning and sequencing. | the phylogenetic diversity of an oligotrophic marine picoplankton community was examined by analyzing the sequences of cloned ribosomal genes. this strategy does not rely on cultivation of the resident microorganisms. bulk genomic dna was isolated from picoplankton collected in the north central pacific ocean by tangential flow filtration. the mixed-population dna was fragmented, size fractionated, and cloned into bacteriophage lambda. thirty-eight clones containing 16s rrna genes were identifie ... | 1991 | 2066334 |
| fe (ii)-chelates based on redox-active pyridoxal-betaines as c-centered radicals causing single- and double-strand scissions to dna. | the ability of 1-[n-ethoxycarbonylmethylpridoxylidenium]-2-[2'- pyridyl]hydrazine bromide code name - [l2.9 = l+,x-]-fe(ii) chelate [l2-9-fe(ii)] to induce breaks both in the 43kb linear double-strand lambda phage dna, and in the 4363 base pair supercoiled pbr322 plasmid dna is herein described. neither the free ligand nor fe(ii) alone demonstrated any effect on the dna. the cleaving ability is shown to occur instantaneously under strictly anaerobic conditions, either in the presence or absence ... | 1991 | 2071028 |
| the par region of psc101 affects plasmid copy number as well as stability. | the par locus is a segment of psc101 that has been identified as a cis-acting determinant of plasmid stability. we show that par also determines copy number and must, therefore, play a role in plasmid replication. the segregation defect, but not the copy-number reduction, of par- replication origins is completely suppressed by a short sequence from the bacteriophage lambda gene o which is present in plasmid pko-4. thus, replication and segregation functions are separable from each other. | 1990 | 2082144 |
| cloning of the amino terminal nucleotides of the antigen i/ii of streptococcus sobrinus and the immune responses to the corresponding synthetic peptides. | a portion of the antigen i/ii (spaa, b, p1) gene of streptococcus sobrinus 6715, containing the coding sequence for the amino terminal 684 amino acids of the protein, was cloned in bacteriophage lambda gt10. selection was by immunological detection using a polyclonal antiserum to the antigen i/ii from strep. mutans. from the amino acid sequence, peptides were synthesized, 15 amino acids in length, that covered the entire sequence. in total, 260 synthetic peptides were synthesized and evaluated f ... | 1990 | 2088235 |
| cloning and nucleotide sequence of the ispa gene responsible for farnesyl diphosphate synthase activity in escherichia coli. | the molecular cloning and the determination of the nucleotide sequence of the ispa gene responsible for farnesyl diphosphate (fpp) synthase [ec 2.5.1.1] activity in escherichia coli are described. e. coli ispa strains have temperature-sensitive fpp synthase, and the defective gene is located at about min 10 on the chromosome. the wild-type ispa gene was subcloned from a lambda phage clone containing the chromosomal fragment around min 10, picked up from the aligned genomic library of kohara et a ... | 1990 | 2089044 |
| the nucleotide and deduced amino acid sequences of ecori fragment containing the 5'-terminal region of clostridium botulinum type e toxin gene cloned from mashike, iwanai and otaru strains. | chromosomal dnas were extracted from toxigenic three clostridium botulinum type e strains isolated from food-borne botulism. after digestion by ecori, the fragments were cloned into escherichia coli by using bacteriophage lambda gt11 and screened with monoclonal antibody recognizing the light chain component of botulinum type e toxin. the fragments (about 1 kbp size) cloned from each strain were recloned into a plasmid vector puc118. the e. coli cells transformed with the recombinant plasmids pr ... | 1990 | 2098632 |
| cloning and expression of dratg genes from azospirillum lipoferum. | a genomic library of azospirillum lipoferum was constructed with phage lambda embl4 as vector. from this library, the genes encoding dinitrogenase reductase adp-ribosyltransferase (drat), drat, and dinitrogenase reductase-activating glycohydrolase (drag), drag, were cloned by hybridization with the heterologous probes of rhodospirillum rubrum. as in r. rubrum, drat is located between drag and nifh, the gene encoding dinitrogenase reductase (a substrate for the drag/drat system). in the crude ext ... | 1990 | 2107127 |
| bacterial expression of immunoglobulin vh proteins. | a bacterial expression system in escherichia coli has been developed that produces as much as 10 mg/l of culture of the vh protein associated with monoclonal antibodies specific for the 5-dimethylaminonaphthalene-2-sulfonyl (dns) group. this system has been applied to the expression of the vh genes derived from a low-affinity, igm-producing hybridoma and from a high-affinity, igg-producing cell line. the plasmid vectors (contributed by dr william f. studier) utilize a t7 expression cassette whos ... | 1990 | 2107393 |
| selective amplification of an mrna and related pseudogene for a human adp-ribosylation factor, a guanine nucleotide-dependent protein activator of cholera toxin. | adp-ribosylation factors (arfs) are approximately 20-kda proteins that act as gtp-dependent allosteric activators of cholera toxin. with deoxyinosine-containing degenerate oligonucleotide primers corresponding to conserved gtp-binding domains in arfs, the polymerase chain reaction (pcr) was used to amplify simultaneously from human dna portions of three arf genes that include codons for 102 amino acids, with intervening sequences. amplification products that differed in size because of differenc ... | 1990 | 2107548 |
| a heterogeneous double antibody enzyme-linked immunoassay to measure beta-galactosidase fusion protein. | a rapid and sensitive enzyme-linked immunoassay (elisa) to quantitate recombinant fusion proteins encoded by cloned cdna in the bacteriophage lambda gt11 is described. since the fusion protein is expressed in an equimolar ratio to beta-galactosidase, the assay derives the concentration of the recombinant protein in total bacterial lysates or pure preparations from the measurement of beta-galactosidase with an enzyme-linked immunoassay. this assay is a useful technique to measure the recombinant ... | 1990 | 2110194 |
| excretion into the culture medium of a bacillus beta-glucanase after overproduction in escherichia coli. | the beta-glucanase gene (bgl) from bacillus amyloliquefaciens was expressed in e. coli csh 55 under the control of the pr promoter of phage lambda that is repressed by the thermosensitive repressor c1857. production of beta-glucanase was drastically stimulated by a temperature shift to 42 degrees c. this overexpression of the bgl gene (about 20% of the total cellular protein) led to an almost complete excretion of the otherwise periplasmic protein into the extracellular medium, beta-glucanase ac ... | 1990 | 2114118 |
| fundamental study on the mechanism of dna degradation in tissues fixed in formaldehyde. | the mechanism of dna degradation and its clinical applications were examined. when purified lambda phage and extracted liver dna were fixed in phosphate buffered formaldehyde, the dna did not degrade, but there was incomplete digestion with endonuclease. rat liver tissues were fixed under various conditions and dna extracted. immediate fixation with buffered formaldehyde at low temperature, or the addition of edta to buffered formaldehyde blocked the dna degradation. analysis of pulsed field gel ... | 1990 | 2120290 |
| a human metallothionein pseudogene containing ag/ct repetitive elements. | a lambda phage recombinant clone, 25 s, which contains a 15.5-kb ecori human genomic dna fragment, has been characterized. restriction mapping and southern blot hybridization indicated a 3.0-kb hindiii fragment containing metallothionein (mt)-like sequences. several interesting features were found upon comparison of this nucleotide sequence with that of other human mt genes: (1) sequences representing the 5' regulatory region, the 5' untranslated region, and the first exon are not contained in t ... | 1990 | 2120457 |
| [activation of the alarm response of escherichia by antibiotics]. | the data on the effect of antibiotics suppressing the synthesis of protein on the activation of the sos-system are presented. the action of tetracycline, chloramphenicol rifampicin and nalidixic acid, a well-known activator of sos-response, has been studied. the short-term action of inhibitory concentrations and the prolonged action of subinhibitory concentrations of these preparations on the activity of genes rec a and sul a and the induction of the synthesis of phage lambda have been considere ... | 1990 | 2124020 |
| isolation and characterization of coml, a transcription unit involved in competence development of bacillus subtilis. | using the transformation-deficient mutant m465, which was previously isolated by means of insertional mutagenesis with plasmid phv60, a transcription unit coml required for genetic competence of bacillus subtilis was identified. a chromosomal dna fragment flanking the inserted phv60 was isolated and used to screen two different libraries of b. subtilis dna in phage lambda embl4 and lambda embl12, respectively. with the aid of six recombinant phages that hybridize with this chromosomal fragment a ... | 1990 | 2125113 |
| celb, a gene coding for a bifunctional cellulase from the extreme thermophile "caldocellum saccharolyticum". | "caldocellum saccharolyticum" is an obligatory anaerobic thermophilic bacterium. a gene from this organism, designated celb, has been cloned in escherichia coli as part of a bacteriophage lambda gene library. this gene produces a thermostable cellulase that shows both endoglucanase and exoglucanase activities on test substrates and is able to degrade crystalline cellulose to glucose. the sequence of celb has homology with both exo- and endoglucanases described by others. it appears to have a cen ... | 1990 | 2126700 |
| structure of the bacteriophage lambda cohesive end site: bent dna on both sides of the site, cosn, at which terminase introduces nicks during chromosome maturation. | packaging of lambda dna is mediated by the phage-encoded enzyme, terminase, which acts at a site termed cos. cos consists of cosb, the site where terminase binds lambda dna, and cosn, the site where nicks are introduced to generate the cohesive ends of virion dna. cos contains multiple binding sites for gpnu1, the small subunit of terminase, and integration host factor (ihf), an escherichia coli dna binding protein. polyacrylamide gel electrophoresis of circularly permuted segments of cos dna ha ... | 1990 | 2136780 |
| application of an efficient strategy with a phage lambda vector for constructing a physical map of the amyloplast genome of sycamore (acer pseudoplatanus). | amyloplasts were isolated from a heterotrophic culture cell line of a woody plant, sycamore (acer pseudoplatanus), and their dna was purified. conventional procedures for making a physical map were not easily applicable to the amyloplast dna, since the yield of dna was too low and the presence of repeated sequences interfered with the analysis. therefore, the pieces of amyloplast dna starting with a few micrograms of dna were cloned in the lambda fix vector, which is a derivative of lambda embl ... | 1990 | 2136984 |
| transcription of a bacteriophage lambda dna site blocks growth of escherichia coli. | the rap mutation in escherichia coli prevents the growth of bacteriophage lambda. phage mutations that overcome rap inhibition (bar) have been mapped to loci in the pl operon. we cloned and sequenced three mutations in two of these loci: baria to the left arm of the lambda attachment site (attp) and barii in the ssb (ea10) gene. the mutations represent single base-pair changes within nearly identical 16-base-pair dna segments. each mutation disrupts a sequence of dyad symmetry within the segment ... | 1990 | 2137118 |
| oligomerization of the bacteriophage lambda s protein in the inner membrane of escherichia coli. | western blot (immunoblot) analysis of cell extracts from induced bacteriophage lambda lysogens probed with s-protein-specific antibody (raised against an s--beta-galactosidase fusion protein) demonstrated that the bacteriophage lambda s protein begins to appear 10 min after phage induction and is localized to the inner membrane at all times during the lytic cycle. between 100 and 1,000 molecules of s protein per cell were present at the time of phage-induced lysis. western blots of chemically cr ... | 1990 | 2137120 |
| mutations in the bacteriophage lambda pl/ol region that spontaneously occur in plasmid prpz126. | in a previous study (chen and porter, 1988), we isolated spontaneous mutations in a test plasmid that had occurred under non-selective conditions and assigned them to 1 of 6 different categories or groups. the test plasmid, prpz126, is a pbr322 derivative containing the bacteriophage lambda immunity region with the ci857 allele so that plasmid-containing cells shifted to 42 degrees c survive only if the expression of the lambda kil gene is prevented by mutation. 75% of the total spontaneous muta ... | 1990 | 2137195 |
| crystallization and preliminary x-ray characterization of maltoporin from escherichia coli. | crystals of maltoporin (the bacteriophage lambda receptor of escherichia coli) that diffract x-rays to 3 a resolution can be grown reproducibly. maltoporin is an integral membrane protein, which forms a channel in the e. coli outer membrane that specifically facilitates the diffusion of maltose and maltodextrins. the crystals have a rhombic prismatic habit and belong to the orthorhombic space group c222(1) with unit cell dimensions a = 130 a, b = 213 a and c = 216 a. x-ray structure determinatio ... | 1990 | 2137884 |
| field inversion gel electrophoresis applied to the rapid, multi-enzyme restriction mapping of phage lambda clones. | 1990 | 2138731 | |
| evidence for the double-strand break repair model of bacteriophage lambda recombination. | we have obtained evidence for the repair of double-strand gaps promoted by the red function of bacteriophage lambda. a double-strand gap was made in one of the two regions of homology in an inverted orientation on a plasmid dna molecule. the gapped plasmid was introduced into escherichia coli cells expressing the red alpha (exo) and red beta (bet) genes of lambda. the gap was repaired by dna synthesis copying an intact duplex. this gap repair was sometimes accompanied by reciprocal recombination ... | 1990 | 2138786 |
| direct cloning of cdna inserts from lambda gt11 phage dna into a plasmid vector by a novel and simple method. | bacteriophage lambda gt11 has been used quite extensively for producing cdna libraries. the cdna inserts are usually subcloned into a plasmid vector for large scale production and analysis. however, isolating the recombinant dna of interest from the phage clones can be a tedious task. since the e. coli strain y1088 used for lambda gt11 phage infection carries a pbr322-derived plasmid endogenously, we reasoned that this endogenous plasmid could be used directly for cloning the cdna phage insert. ... | 1990 | 2138901 |
| purification of bacteriophage dna by gel filtration chromatography. | two fast and effective methods for high-scale purification of linear phage lambda dna and circular double-stranded m13 replicative form are presented. a substantial reduction of time is attained by avoiding the long-term cscl gradient centrifugations and dialysis common to standard procedures. biologically active dna preparations, free of chromosomal dna and rna, are obtained by including a simple gel filtration chromatography as the last step of purification. yields are comparable to those from ... | 1990 | 2138902 |
| modified bacteriophage lambda promoter vectors for overproduction of proteins in escherichia coli. | a new series of expression vectors that direct high-level overproduction of gene products in escherichia coli is described. all contain strong bacteriophage lambda promoters, pr and pl, arranged in tandem so that both promote transcription into genes inserted into or between unique restriction sites. the vectors also direct expression of the lambda ci857 gene (from its natural promoter, pm), which enables their use in any e. coli host strain to effect controlled expression by shifting the temper ... | 1990 | 2139621 |
| integration of bacteriophage lambda into the cryptic lambdoid prophages of escherichia coli. | bacteriophage lambda missing its chromosomal attachment site will integrate into reca+ escherichia coli k-12 and c at the sites of cryptic prophages. the specific regions in which these recombination events occur were identified in both lambda and the bacterial chromosomes. a noti restriction site on the prophage allowed its physical mapping. this allowed us to identify the locations of rac, qin, and qsr' cryptic prophages on the noti map of e. coli k-12 and, by analogy, to identify the cryptic ... | 1990 | 2139644 |
| mutations in the atp-binding domain of escherichia coli rho factor affect transcription termination in vivo. | five mutant rho proteins, representing alterations at three different locations in the escherichia coli rho gene that affect atp hydrolytic activity but not rna binding, were examined in vivo for function at the rho-dependent is2 and bacteriophage lambda tr1 terminators. the altered amino acids in rho are located at highly conserved residues near the beta 1 and beta 4 strands of the hydrophobic atp-binding pocket that is structurally similar to the f1-type atpases and adenylate kinase. the rna-d ... | 1990 | 2139646 |
| a minor arginine trna mutant limits translation preferentially of a protein dependent on the cognate codon. | the escherichia coli argu gene encodes a rare arginine trna (anticodon ucu) that translates the similarly rare aga codon. the argu10(ts) mutation is a transition that changes the first nucleotide of the mature trna from g to a, presumably destabilizing the acceptor stem. this mutation, when present in haploid condition in the chromosome, reduces the growth rate at 30 degrees c and results in cessation of growth after 60 to 90 min at 43 degrees c. the mutation also preferentially limits (compared ... | 1990 | 2139647 |
| integration host factor stimulates the phage lambda pl promoter. | escherichia coli integration host factor (ihf) is a small dimeric protein that binds to a specific dna consensus sequence and produces dna bending. transcription from the bacteriophage lambda pl promoter is stimulated three- to fourfold by ihf both in vivo and in vitro. ihf binds with high-affinity to two tandem sites located just upstream from the pl promoter and enhances the formation of rna polymerase-promoter closed complexes. the rate of isomerization to open complex is not influenced by ih ... | 1990 | 2140136 |
| enhanced resolution of dna restriction fragments: a procedure by two-dimensional electrophoresis and double-labeling. | a probe-free method was developed to detect dna rearrangement in bacteria based on the electrophoretic separation of twice-digested restriction fragments of genomic dna into a two-dimensional (2-d) pattern. the first restriction enzyme digestion was done in solution, followed by electrophoresis of the restriction fragments in one dimension. a second restriction enzyme digestion was carried out in situ in the gel, followed by electrophoresis in a second dimension perpendicular to the first electr ... | 1990 | 2140194 |
| on the possibility of obtaining a physical map of genomes by photoelectron imaging. | photoelectron imaging provides the possibility of a new method of mapping chromosomes. the basic concept is to cause dna to emit electrons under the action of uv light. the criteria which must be met to map genomes by photoelectron imaging are set forth and discussed. forming an image of the dna by accelerating and focusing the electrons is a necessary but not sufficient condition for genome mapping. equally important is to identify wavelengths of uv light which will cause selective emission fro ... | 1990 | 2140278 |
| phage lambda cdna cloning vectors for subtractive hybridization, fusion-protein synthesis and cre-loxp automatic plasmid subcloning. | we describe the construction and use of two classes of cdna cloning vectors. the first class comprises the lambda exlx(+) and lambda exlx(-) vectors that can be used for the expression in escherichia coli of proteins encoded by cdna inserts. this is achieved by the fusion of cdna open reading frames to the t7 gene 10 promoter and protein-coding sequences. the second class, the lambda shlx vectors, allows the generation of large amounts of single-stranded dna or synthetic crna that can be used in ... | 1990 | 2140336 |
| specificity of the in vitro interaction of methylfurfural with dna. | methylfurfural (mf) or 5-methyl 2-furaldehyde is a dietary mutagen and is present in various food products and beverages. alkaline unwinding of calf thymus dna and the protection of cleavage sites in lambda phage dna from the action of various restriction enzymes was used to study the interaction of mf with dna. alkaline unwinding experiments showed the formation of an increasing number of strand breaks in duplex dna, both with increasing mf concentration and time of reaction. treatment of lambd ... | 1990 | 2140425 |
| bacteriophage lambda dna: the beginning of the end. | 1990 | 2140565 | |
| the role of the direct repeat in qut-controlled antitermination in phage lambda. | for antitermination of transcription from the late p'r promoter of phage lambda, a cis-acting qut sequence, which overlaps with p'r, is required, together with the product of lambda gene q. using our bspmi-mediated multicycle technique for generation of precise deletions, we have confirmed that deletions removing dna downstream of +18 bp (counted from the p'r-controlled transcriptional start point s'r = +1) do not affect the efficiency of qut antitermination; at the same time we found that delet ... | 1990 | 2140632 |
| plasmid and bacteriophage lambda-dna show differential replication characteristics following injection into fertilized eggs of xenopus laevis: dependence on period and site of injection. | the fate of dna injected into in vitro fertilized eggs of xenopus laevis during subsequent early embryogenesis was investigated by changing the time period and the area of injection. form i/ii plasmid dna was found to be preferentially replicated in embryos which had been injected 60-65 min after fertilization into the animal half of the fertilized egg, irrespective of the presence of a eukaryotic origin of replication sequence element in the dna probe used for injection. in the experiments wher ... | 1990 | 2140953 |
| renaturation of denatured lambda repressor requires heat shock proteins. | the temperature-sensitive bacteriophage lambda ci857 repressor protein rapidly renatures after thermal inactivation. e. coli mutants in the heat shock protein genes dnak, dnaj, and grpe do not efficiently reactivate heat-denatured repressor. our results suggest that protein refolding is promoted by heat shock proteins and that such a process is the basis of the homeostatic role played by these proteins in the heat shock response. | 1990 | 2140957 |
| structure and inherent properties of the bacteriophage lambda head shell. vii. molecular design of the form-determining major capsid protein. | some mutations in the major capsid protein (gpe) of lambda phage can alter the size and shape of the head shell or block the pathway of head maturation. previous studies on the classification of such mutants showed that there are at least five functional sites on the gpe molecule. in this study, we determined the amino acid exchanges by dna sequencing to elucidate the molecular design of the form-determining multifunctional protein gpe. in addition, we characterized the mutated gpe molecules by ... | 1990 | 2141087 |
| use of regulated cell lysis in a lethal genetic selection in escherichia coli: identification of the autoinducer-binding region of the luxr protein from vibrio fischeri atcc 7744. | a lethal genetic selection utilizing the bacteriophage lambda lysis genes (s, r, rz) has been developed and used in conjunction with a luminescence screen to allow the isolation and characterization of six missense mutations and two nonsense mutations in the luxr gene from vibrio fischeri atcc 7744. a transcriptional fusion of the lysis genes in operonr downstream of a truncated luxi gene allows control of cell lysis by the addition of synthetic autoinducer to the growth medium. the six missense ... | 1990 | 2141835 |
| differential diagnosis of taenia saginata and taenia solium with dna probes. | a size selected genomic dna library was constructed using dna extracted from taenia saginata. the dna was digested using the restriction enzyme ecor1 under star conditions and the 2-4 kbase fraction, selected following sucrose density-gradient separation, was cloned in the bacteriophage lambda gt 10. a panel of cestode dnas including taenia saginata, taenia solium, taenia taeniaeformis, taenia crassiceps, echinococcus granulosus and dnas of bovine, porcine and human origin were used in conjuncti ... | 1990 | 2141926 |
| solution structure of phage lambda half-operator dna by use of nmr, restrained molecular dynamics, and noe-based refinement. | the structure of a dna decamer comprising the left half of the or3 operator from bacteriophage lambda is determined in solution by using nuclear magnetic resonance spectroscopy and restrained molecular mechanics calculations. nuclear magnetic resonance assignments for nonexchangeable protons are obtained by two-dimensional correlated and nuclear overhauser effect (noe) spectroscopies. exchangeable proton resonances are assigned by one-dimensional noe experiments. coupling constant measurements f ... | 1990 | 2141998 |
| isolation and sequence of the canine pancreatic phospholipase a2 gene. | a genomic library has been constructed in embl3 lambda phage using high molecular mass dna isolated from canine spleen. a cdna clone, shown to code for preprophospholipase a2 which is processed to the prosecretory form prior to release from secretory cells, was used to identify a lambda clone which contains the complete phospholipase a2 gene. restriction enzyme and dna sequence analysis indicate that the primary transcriptional unit for the phospholipase gene, approximately 9.0 kb, is organized ... | 1990 | 2142076 |
| cloning and expression in escherichia coli of mycoplasma gallisepticum antigens recognized by sera from infected chickens. | a clone bank of mycoplasma gallisepticum (mg) strain a5969 dna was prepared in the expression vector phage lambda gt11. approximately 75% of the resulting phages were recombinants, based upon the insertional inactivation of the lacz gene of the vector. clones were screened immunologically with serum prepared from specific-pathogen-free white leghorn chickens that had been infected with aerosolized mg. approximately 250 clones, or less than 1% of the recombinant phage, reacted positively to vario ... | 1990 | 2142422 |
| a comparison of the effects of single-base and triple-base changes in the integrase arm-type binding sites on the site-specific recombination of bacteriophage lambda. | triple-base changes were made in each of the five integrase (int) arm-type binding sites of bacteriophage lambda. these triple changes, called ten mutants, were compared with single-base changes (hen mutants) for their effects on integrative and excisive recombination. the presence of ten or hen mutations in the p1, p'2, or p'3 sites inhibited integration, but the ten p'3 mutant was 10-fold more defective than the analogous hen mutant. the results with these mutants suggest that the p1, p'2, p'3 ... | 1990 | 2142765 |
| analysis of mutations in the ninr region of bacteriophage lambda that bypass a requirement for lambda n antitermination. | two mutations in the ninr region of bacteriophage lambda that bypass a requirement for antitermination have been studied. one mutation, byp, has been cloned and mapped by marker rescue to a 417-base-pair segment in the ninr region of the genome. analysis of the byp mutation by using promoter detection vectors, dna sequencing, and s1 nuclease analysis showed that the byp mutation created a new promoter that transcribed gene q. the second mutation analyzed was the deletion nin3. sequence analysis ... | 1990 | 2142940 |
| break-join recombination in phage lambda. | in phage lambda, when dna replication is blocked, recombination mediated by the red pathway occurs only near the double-chain break site, cos, that defines the termini of the virion chromosome. the recombinants initiated by cos contain newly synthesized dna near cos, in amount corresponding to a few percent of the length of lambda. a restriction enzyme cut delivered to one parent far from cos results in elevated recombination near the restriction site. recombinants induced by this cut have a sim ... | 1990 | 2143162 |
| alterations in the p'r promoter of coliphage lambda modify both its activity and interaction with the integration host factor (ihf). | a limited number of deletion/insertions and a point mutation in the -35 region of the p'r promoter of phage lambda were examined and found to influence both transcription and its repression by the integration host factor (ihf). positive effects on transcription (in the absence of ihf) are small (up to 1.4-fold) and are caused by a deletion-substitution upstream of the -35/ihf site. up to three base changes in the -35 promoter element seem to be tolerated, with only a small negative effect on tra ... | 1990 | 2143267 |
| stimulation of mutations suppressing the loss of replication control by small alcohols. | transient exposure of lysogenic escherichia coli cells to small alcohols stimulated the frequency of mutations suppressing the lethal loss of replication control from a prophage fragment of bacteriophage lambda. the stimulation in mutation frequency paralleled the effect of mutagenic agents, and in this sense the alcohols behaved as mutagens. 10-min treatments above distinct threshold concentrations at 23%, 18%, 10% and 4% (v/v) were required in order for methanol, ethanol, isopropanol and propa ... | 1990 | 2143557 |
| a bacterial virulence determinant encoded by lysogenic coliphage lambda. | although phage lambda represents a well studied biological systems, it has certain features that remain obscure. among these is the function of the roughly one third of the phage genome dispensable for growth in the laboratory, yet retained despite undoubted pressure to economize. here we report that these 'accessory' sequences contain two genes which are expressed during lysogeny, and encode host-cell envelope proteins. one of these is lom, the product of which is found in the bacterial outer m ... | 1990 | 2144037 |
| isolation and characterization of dnaj null mutants of escherichia coli. | bacteriophage lambda requires the lambda o and p proteins for its dna replication. the rest of the replication proteins are provided by the escherichia coli host. some of these host proteins, such as dnak, dnaj, and grpe, are heat shock proteins. certain mutations in the dnak, dnaj, or grpe gene block lambda growth at all temperatures and e. coli growth above 43 degrees c. we have isolated bacterial mutants that were shown by southern analysis to contain a defective, mini-tn10 transposon inserte ... | 1990 | 2144273 |
| a new assay for o6-alkylguanine-dna-alkyltransferase to determine dna repair capacities using lambda-phage dna as substrate. | one o6-methylguanine (o6-meg) was introduced into each bamhi site of lambda-phage dna as a substrate for the determination of the dna repair protein o6-alkylguanine-dna-alkyltransferase. a new assay using as the detection group 32p-labeled phosphate introduced at the 3' position of the modified nucleoside by incorporation of 32p-labeled ttp in the 3'-neighboring position proved highly sensitive: 10(-16) mol of the dna lesion was still easily detectable. this dna, which has greater than 1000 bp r ... | 1990 | 2145087 |
| the p53 tumour suppressor protein is phosphorylated at serine 389 by casein kinase ii. | the entire coding sequence of wild-type mouse p53 was expressed in escherichia coli under control of the pl promoter of bacteriophage lambda. the bacterial p53 protein had identical mobility to p53 from sv3t3 cells on sds polyacrylamide gels and was recognized in bacterial lysates by three p53-specific monoclonal antibodies, including pab246 which is specific for wild-type mouse p53. immunoprecipitates of the bacterial p53 were phosphorylated by a highly purified preparation of rat casein kinase ... | 1990 | 2145148 |
| characterization of the human platelet glycoprotein iiia gene. comparison with the fibronectin receptor beta-subunit gene. | this study was designed to determine the structure of the gene for glycoprotein (gp) gpiiia, the beta-subunit of the platelet membrane gpiib-iiia complex. the complexity of the gene was determined after southern analysis of human chromosomal dna. overlapping genomic clones were isolated from cosmid and phage lambda libraries that contained the entire coding unit of the human gene for the mature gpiiia protein. the genomic clones spanned approximately 60 kilobase pairs of human dna sequence. the ... | 1990 | 2145280 |
| [pleiotropic effect of the rpoc mutation in escherichia coli k-12 reducing the frequency of lysogenization by phage lambda]. | we described earlier the isolation of lfl25 mutation reducing the frequency of lysogenization of mutant cells by phage lambda (lyca phenotype). the mutation is mapped at present in the rpoc gene coding for the beta' subunit of bacterial rna polymerase and named rpoc90. it is dominant and causes decrease in pools of some branched amino acids, pyrimidines and thiamine (vitamin b1) in mutant cells. combination of rpoc90 mutation with some rif-r mutations strengthens both the lyca phenotype and defi ... | 1990 | 2146182 |
| nucleotide sequence of the phage lambda gt11 saci-kpni lacz region. | the nucleotide sequence of the lambda gt11 saci-kpni region, surrounding the unique ecori cloning site, was directly determined. this sequence previously had to be compiled from several diverse sources. the direct sequence confirms the sequence predicted from the compilation and pinpoints other unique restriction enzyme targets in the region for use in subcloning. | 1990 | 2146187 |
| chromosome rearrangements induced by recombinant coliphage lambda placmu. | operon fusions to lacz, commonly used to study bacterial gene expression in vivo, are normally constructed using phage derivatives such as lambda placmu53 or mud-1. these derivatives contain a part of trp operon, and we have found that, when integrated into the chromosome, recombination can occur at high frequency between this trp dna and the chromosomal trp operon leading to chromosomal inversions which fuse lacz to the trp promoter. large segments of the chromosome can be inverted by such rear ... | 1990 | 2146189 |
| theoretical and experimental analysis of the phage lambda genetic switch implies missing levels of co-operativity. | the behavior of the cro-repressor switch in phage lambda, a temperate phage of escherichia coli, is described at the organismal level within a dynamical system framework. the molecular biology of the switch has been well characterized up to the level of the regulation of transcription initiation. in this paper we construct a description of a lysogen whose prophage is mutated in certain genes, so that the switch is functionally isolated from the rest of the phage genome. such a lysogen has two st ... | 1990 | 2146446 |
| an analysis of the role of host factors in transcription antitermination in vitro by the q protein of coliphage lambda. | we used two different approaches to study the requirement for escherichia coli nus factors for the activity of bacteriophage lambda late antiterminator q. using an in vitro coupled transcription-translation assay, based on q-dependent synthesis of galactokinase from a pr'-tr'-galk template, we showed that mutations in the host nusb and nuse genes do not affect q activity. a mutation in nusa (nusa1) only partially affects q action at all temperatures tested. defective q function in the nusa1 muta ... | 1990 | 2146485 |
| alcohol treatment of defective lambda lysogens is deletionogenic. | we ascertained that transient exposure to ethanol, above 18%, was deletionogenic to an escherichia coli strain with a fragment (12.5 kb) of bacteriophage lambda integrated within the chromosome. the lambda attl b.p' through p fragment provided a forward selection for mutants, and a target for mutagenesis. the cells were killed by thermal derepression of transcription and replication of the lambda fragment when transferred from 30 degrees to 42 degrees c. survivor mutants, capable of forming colo ... | 1990 | 2146486 |
| selection for mutations in the pr promoter of bacteriophage lambda. | insertion of dna containing pr, the early rightward promoter of bacteriophage lambda, is lethal to m13-derived vectors when the promoter directs transcription (using the '+' strand as template) toward the m13 origin of replication (ori). lethality can be relieved by mutation of pr, repression of the promoter by the lambda cl repressor, or by insertion of a strong transcription terminator between pr and ori. we have used selection for plaque formation in the absence of repressor to isolate 14 dif ... | 1990 | 2146590 |
| identification of human antibody fragment clones specific for tetanus toxoid in a bacteriophage lambda immunoexpression library. | we have applied a molecular biology approach to the identification of human monoclonal antibodies. human peripheral blood lymphocyte mrna was converted to cdna and a select subset was amplified by the polymerase chain reaction. these products, containing coding sequences for numerous immunoglobulin heavy- and kappa light-chain variable and constant region domains, were inserted into modified bacteriophage lambda expression vectors and introduced into escherichia coli by infection to yield a comb ... | 1990 | 2146680 |
| protein-dna conformational changes in the crystal structure of a lambda cro-operator complex. | the structure of a complex of bacteriophage lambda cro protein with a 17-base-pair operator has been determined at 3.9-a resolution. isomorphous derivatives obtained by the synthesis of site-specific iodinated dna oligomers were of critical importance in solving the structure. the crystal structure contains three independent cro-operator complexes that have very similar, although not necessarily identical, conformations. in the complex, the protein dimer undergoes a large conformational change r ... | 1990 | 2146682 |
| production of lambda-phi 29 phage chimeras. | proheads of bacteriophage lambda which carry the connector of phage phi 29 instead of that of lambda have been produced in vitro. these hybrid proheads have a structure similar to that of normal lambda proheads. furthermore, the chimeric proheads can package both lambda and phi 29 dna. these data show that the connector domains involved in both head assembly and dna packaging are functionally similar. the dna-containing lambda-phi 29 proheads can be complemented in vitro with phi 29 tails to yie ... | 1990 | 2146805 |
| [rapid restriction mapping of dna cloned in cosmid or lambda phage vectors]. | a procedure for rapid restriction mapping of cosmid or lambda phage clones has been developed. the mapping of cosmid is based on linearization of circular cosmid dna in vitro by the phage lambda terminase. partial digestion products are selectively labelled at the right or left cos cohesive termini by hybridization with [32p] oligonucleotides complementary to the single-strand cos end. after gel electrophoresis and autoradiography, the restriction map can be directly determined from the "ladder" ... | 1990 | 2146971 |
| lysis protein s of phage lambda functions in saccharomyces cerevisiae. | the lambda s lysis gene was cloned into a saccharomyces cerevisiae expression vector under gal1 control. induction with galactose in s. cerevisiae terminated cell growth and prevented colony formation. several membrane proteins immunoreactive with anti-s antibody accumulated in the membranes, indicating that sodium dodecyl sulfate-resistant oligomers of s are formed, similar to those observed in the membranes of escherichia coli cells killed by expression of the s gene. these observations sugges ... | 1990 | 2147680 |
| a short dna sequence from lambda phage inhibits protein synthesis in escherichia coli rap. | the escherichia coli rap mutant inhibits vegetative growth of bacteriophage lambda. phage mutations termed bar, which overcome the rap defect, have been mapped to three genetic loci in the pl operon. plasmids with a lambda wild-type bar dna segment cloned downstream from an active promoter cannot be maintained in rap mutant bacteria. the viability of a rap mutant strain decreases rapidly after induction of transcription through bar regions present on plasmids. under these (restrictive) condition ... | 1990 | 2147720 |
| receptor-recognizing proteins of t-even type bacteriophages. the receptor-recognizing area of proteins 37 of phages t4 tuia and tuib. | escherichia coli phages of the t4 family (t4, tuia, tuib) recognize their cellular receptors by means of a c-terminal region of protein 37; a dimer of this polypeptide (1026 residues in t4) is located at the distal part of the long tail fibers. virions of the t2 family use protein 38 (which is attached to the free end of protein 37) for this purpose. the corresponding areas of genes 37 belonging to tuia and tuib were cloned and sequenced. comparison of the deduced protein primary structures, inc ... | 1990 | 2147721 |
| sequence requirements for coiled-coils: analysis with lambda repressor-gcn4 leucine zipper fusions. | a genetic system was developed in escherichia coli to study leucine zippers with the amino-terminal domain of bacteriophage lambda repressor as a reporter for dimerization. this system was used to analyze the importance of the amino acid side chains at eight positions that form the hydrophobic interface of the leucine zipper dimer from the yeast transcriptional activator, gcn4. when single amino acid substitutions were analyzed, most functional variants contained hydrophobic residues at the dime ... | 1990 | 2147779 |
| high level expression of porcine growth hormone in escherichia coli from an expression vector containing bacteriophage lambda pl and n gene untranslated region. | an escherichia coli expression vector, pg408n containing a pl promoter and the upstream untranslated region of the n gene of bacteriophage lambda has been constructed. we have designed a pvuii site immediately behind the untranslated region. a dna fragment starting with an initiation codon atg could be inserted into this site for expression. this vector also contains 7 additional cloning sites downstream from the pvuii site. a gene could be cloned into one of these sites and the 5' sequence of t ... | 1990 | 2148085 |
| temperature-mediated regulation and downstream inducible selection for controlling gene expression from the bacteriophage lambda pl promoter. | we have examined in detail the effects of various induction temperatures on the expression of a heterologous fusion gene controlled by the bacteriophage lambda pl promoter in a heat-inducible escherichia coli expression system which utilizes the cits857 repressor. experiments performed over a temperature range spanning 29-42 degrees c indicate that, under our conditions, temperatures as low as 29 degrees c may be required to fully repress the ci857-controlled transcription from pl, and that the ... | 1990 | 2148296 |
| a phosphate group at the cos ends of phage lambda dna is not a prerequisite for in vitro packaging: an alternative method for constructing genomic libraries using a new phasmid vector, lambda pgy97. | it is shown here that the phosphate groups at the cos ends of phage lambda dna are not a prerequisite for in vitro packaging. molecules with phosphatase-treated cos ends are packaged in vitro as efficiently as native lambda dna. this observation can be used for an alternative strategy to improve the efficiency of gene library construction, since cos-cos ligation decreases in vitro encapsidation and infectivity. dephosphorylated cos ends and a new phasmid vector lambda pgy97 have been used to con ... | 1990 | 2148297 |
| detection of large cdna inserts within crude lambda gt11 lysates: a rapid and sensitive method. | a method is presented for the isolation of bacteriophage lambda dna and the rapid identification of large cdna inserts within crude phage lysates. the primary screening of a lambda gt11 cdna library with a 32p-radiolabeled cdna probe yielded 21 putative positive clones. a phage "spot-blot" analysis was employed to quickly screen these potential recombinants. this eliminated 9 of the 21 clones as the result of false positive signals. the remaining 12 recombinant phage were amplified on agarose-ba ... | 1990 | 2148485 |
| transcription-dependent competition for a host factor: the function and optimal sequence of the phage lambda boxa transcription antitermination signal. | ordered development of lambdoid phages relies on systems of transcription termination and antitermination. the phage-encoded n early regulatory proteins, acting with the nus proteins of escherichia coli, modify rna polymerase to a form that overrides many transcription termination signals. these modifications require cis-acting sites, nut, located downstream of the early phage promoters. the nut sites in phages lambda, 21, and p22, which share similarities but are not identical, contain two sign ... | 1990 | 2148536 |
| rnase iii-dependent hydrolysis of lambda cii-o gene mrna mediated by lambda oop antisense rna. | the 77-nucleotide oop antisense rna of bacteriophage lambda complements lambda cii-o mrna in a region that includes 55 nucleotides at the 3' end of the cii gene and 22 nucleotides in the intercistronic region between the cii and o genes. oop rna, produced from multicopy plasmids, inhibits lambda cii gene expression by approximately 100-fold through an rnase iii-dependent mechanism. using primer extension analysis of cellular rna isolated from an induced lambda lysogen that contains an oop dna pl ... | 1990 | 2148537 |
| lambda red-mediated synthesis of plasmid linear multimers in escherichia coli k12. | expression of the red+ and gam+ genes of bacteriophage lambda in plasmids cloned in escherichia coli wild-type cells leads to plasmid linear multimer (plm) formation. in mutants that lack exonuclease i (sbcb sbcc), either of these lambda functions mediates plm formation. in order to determine whether plm formation in sbcb sbcc mutants occurs by conservative (break-join) recombination of circular plasmids or by de novo dna synthesis, thya sbcb sbcc mutants were transferred from thymine- to 5-brom ... | 1990 | 2148608 |
| evidence for the exchange of segments between genomes during the evolution of lambdoid bacteriophages. | heteroduplexes between the dna molecules of 12 lambdoid phages were analysed by electron microscopy. the positions of the regions of base sequence homology between the dna molecules divide them into 35 segments, most of which have a number of alternative forms (alleles), which in general must be functionally homologous but which differ in base sequence and length. the positions of the boundaries between segments in phage lambda show that each segment is probably a gene or a group of genes, and t ... | 1990 | 2149160 |
| mechanism of length determination in bacteriophage lambda tails. | the mechanism of length determination in bacteriophage lambda tails is discussed as a model for regulation in protein assembly systems. the lambda tail is a long flexible tube ending in a conical part and a single tail fiber. its length is exactly determined in the sense that the number of major tail protein (gpv) molecules, which comprise more than 80% of the mass of the tail, is exactly the same in all tails. assembly of gpv is regulated by the initiator complex, which contains the tail fiber ... | 1990 | 2150582 |
| the use of transgenic mice for short-term, in vivo mutagenicity testing. | in order to develop a short-term, in vivo assay to study the mutagenic effects of chemical exposure, transgenic mice were generated using a lambda shuttle vector containing a lacz target gene. following exposure to mutagens, this target can be rescued efficiently from genomic dna prepared from tissues of the treated mice using restriction minus, in vitro lambda phage packaging extract and restriction minus escherichia coli plating cultures. mutations in the target gene appear as colorless plaque ... | 1990 | 2151115 |
| action of an rna site at a distance: role of the nut genetic signal in transcription antitermination by phage-lambda n gene product. | the n gene product of escherichia coli phage lambda is a transcriptional activator that captures the host rna polymerase and modifies it to a termination-resistant form, permitting gene expression in two large polycistronic operons of the phage genome. antitermination in vitro requires at least one host factor called nusa, which directly binds the n protein as well as rna polymerase, and also a transcribed cis-acting site known as nut, within which lies the hypothesized n-recognition signal, box ... | 1990 | 2151659 |
| genetic analysis of bacteriophage lambda integrase interactions with arm-type attachment site sequences. | the bacteriophage p22-based challenge phage system was used to study lambda integrase (int) protein binding to its arm-type recognition sequences in the bacteriophage lambda attachment site. challenge phages were constructed that carried inserts containing either the contiguous p'123 arm-type sites or the single p'1 site within the p22 phage promoter, pant, which is required for expression of antirepressor. if int protein binds to these sequences in vivo, it represses transcription from pant. we ... | 1990 | 2155203 |
| structural and functional properties of the segments of lambda cro mrna that interact with transcription termination factor rho. | termination of transcription at tr1, the rho-dependent terminator between genes cro and cii of bacteriophage lambda, is dependent upon the structure of segments near the 3' end of the nascent cro gene transcript and on contacts between rho protein and a 3' proximal segment called rut. the characteristics of the structure of cro rna in the region from residue 220 to residue 355 in free, isolated rna and in the presence of rho or nusa proteins were analyzed by measuring relative rates of reactivit ... | 1990 | 2157021 |
| site-directed insertion mutagenesis with cloned fragments in escherichia coli by p1 phage transduction. | a cloned gene with an insertion, which was made by introducing cat, was ligated to the cloning site of the phage lambda gt11. p1 phage grown on cells lysogenized with the recombinant lambda phage could transduce the mutant gene into the original site on the escherichia coli chromosome. | 1990 | 2157955 |
| a general method for the transfer of plasmid-borne mutant alleles to the chromosome of klebsiella pneumoniae using bacteriophage lambda: transfer of pqq genes. | a generally applicable method is described for reintroduction of mutant plasmid-borne alleles to the chromosome of klebsiella pneumoniae using bacteriophage lambda. we used this method to make stable chromosomal transposon insertions in genes for biosynthesis of pyrroloquinoline quinone in k. pneumoniae. | 1990 | 2160055 |
| a bacteriophage lambda dna purification procedure suitable for the analysis of dna from either large or multiple small lysates. | a method for the efficient preparation of high quality bacteriophage lambda dna from cleared lysates is described. advantages of the method include high dna yields (typically around 0.8 micrograms of dna/1 ml of cleared lysate), speed of processing (approximately 2 h from lysate to dna), economy, and the absence of any requirement for phenol or chloroform extractions. the technique involves the concentration of phage particles by standard polyethylene glycol precipitation followed by enzymatic t ... | 1990 | 2160201 |
| mapping of insertion element is5 in the escherichia coli k-12 chromosome. chromosomal rearrangements mediated by is5. | we identified phage clones containing insertion element is5 in a set of 476 lambda phage clones carrying chromosomal segments that cover almost the entire chromosome of escherichia coli k-12 w3110. precise locations and orientations of is5 were then determined by cleavage analysis of phage dnas containing them. we mapped 23 copies of is5 (named is5a to is5w) on the w3110 chromosome. among them, ten were identified as the common elements present at the same locations in both chromosomes of w3110 ... | 1990 | 2160543 |
| characterization of transposon insertion out- mutants of erwinia carotovora subsp. carotovora defective in enzyme export and of a dna segment that complements out mutations in e. carotovora subsp. carotovora, e. carotovora subsp. atroseptica, and erwinia chrysanthemi. | soft-rotting erwinia spp. export degradative enzymes to the cell exterior (out+), a process contributing to their ability to macerate plant tissues. transposon (tn5, tn10, tn10-lacz) insertion out- mutants were obtained in erwinia carotovora subsp. carotovora 71 by using plasmid and bacteriophage lambda delivery systems. in these mutants, pectate lyases, polygalacturonase, and cellulase, which are normally excreted into the growth medium, accumulated in the periplasm. however, localization of th ... | 1990 | 2160934 |